This invention has relation to a tool for magnetizing and demagnetizing such articles as iron screwdrivers, for example.
It is known to magnetize soft iron articles such as screwdrivers by placing such article in close proximity to a permanent bar magnet. See U.S. Pat. No. 3,662,303, granted to Arllof in May of 1972; U.S. Pat. No. 3,467,926, granted to Smith in September of 1969; and U.S. Pat. No. 575,679, granted to Hussey in January of 1897.
It is also known to magnetize and to demagnetize using involved, intricate and expensive apparatus and circuits employing direct current surges. See U.S. Pat. No. 2,125,628, granted to Fredrickson in August of 1938 and U.S. Pat. No. 2,996,863, granted to Odell in August of 1961.
Intricate, expensive and elaborate circuitry and apparatus have been employed to demagnetize soft iron articles by providing an alternating current field associated with a demagnetizing coil from which the article to be demagnetized can be withdrawn. See U.S. Pat. No. 3,086,148, granted to Soneki in April of 1963.
Expensive and intricate and involved circuitry and apparatus has been provided to charge a condenser and to discharge the condenser through a coil to magnetize soft iron articles; while at the same time providing circuitry and apparatus to demagnetize by supplying alternating polarity electric current to a coil while the article to be demagnetized is withdrawn from the vicinity of the coil. See U.S. Pat. No. 3,303,398, granted to Barta et al in February of 1967.
None of these prior patents, and no other prior art of which the present applicant and his agents are aware can be utilized to provide a low cost tool directly utilizing ordinary house power and only two movable switches together with a solenoid coil and an iron core to provide a tool which can selectively magnetize or demagnetize soft iron articles.